1. Field of the Invention
Exemplary embodiments relate in general to RFID technology, and in particular to using RFID technology to locate devices. Still more particularly, the present invention relates to a method and system for cost-effectively locating devices using RFID technology.
2. Description of Background
The use of radio frequency (RF) identification (RFID) technology to be alerted of devices that are equipped with an RFID tag (i.e., an electronic tag that emits an RFID signal when triggered by an RF signal) is generally known in the art. In conventional systems, a number of RF transceivers are provided in a monitored environment. These transceivers generate and transmit RF signals in a particular sub-area defined by the strength of the RF signal and location of the RF transceiver relative to the area of projection.
Radio frequency identification is a technology similar in theory to bar code identification. An RFID system consists of an antenna and a transceiver, which read the radio frequency and transfer the information to a processing device, and a transponder, or tag, which is an integrated circuit containing the RF circuitry and information to be transmitted. RFID systems can be used just about anywhere, from clothing tags to missiles to pet tags to food: anywhere that a unique identification system is needed. One of the key differences between RFID and bar code technology is RFID eliminates the need for line-of-sight reading that bar coding depends on.
The problem, however, is that RFID tags located around an antenna answer but do not provide their localization. In some cases, it is interesting to know where the tag is located such that the attached item can be retrieved. So the problem is to get the 3D coordinates of a tag.
Localization with conventional solutions is based on multiple antennas receiving the response from the tag (whose location is being searched) such that the reader by geometric calculation determines the position of the tag. Unfortunately these solutions require the installation of multiple expensive antennas. Also, there is substantial cost in implementing conventional locating systems because the ability to implement the conventional systems on a large scale is limited by the large number of high-logic devices that are required.
A need exists to have a generally applicable solution to overcome these and other limitations found with conventional systems.